Pliny the Elder was the author of an enormous encyclopedia, the Natural History, which, despite many flaws, provides considerable insight into the early Imperial economy. Born in the mid-20s CE, Pliny served in the Roman cavalry as a young man. He began his prolific writing career with a book on throwing javelins, going on to write a biography of Publius Pomponius Secundus (an ex-consul who, Pliny tells us, never belched in his entire life), an account of Rome’s Germanic wars, as well as books on rhetoric, grammar, and Roman history. Unfortunately, none of these works survive. Pliny also worked as a lawyer in Rome, was a close associate of the emperors Vespasian and Titus, and served as a procurator in several provinces. According to his nephew, Pliny the Younger, Pliny devoted every spare moment to study, taking notes on the books he had read to him during dinner, while bathing, and even when being carried through the streets of Rome in a litter. At the time of his death, he commanded the Roman fleet at Misenum.

The Natural History is Pliny’s only surviving work and consists of 37 books covering everything from cosmology to minerals. Despite a poor reputation with respect to prose style, the work has always found plenty of readers. Though dedicated to the Emperor Titus, Pliny claims in his preface that the work is meant for farmers and artisans as well as students. Containing a vast array of minutiae concerning a wide variety of topics, the work is something of a slog to read from beginning to end and has often been excerpted (e.g., for art historians and those interested in ancient science and technology). In recent decades, however, scholars have attempted to appreciate the Natural History as a whole. Andrew Wallace-Hadrill, for example, calls Pliny a “crusader” who “by showing how nature is designed for man, [tried] to persuade man how properly to make use of his natural environment” [“Pliny the Elder and Man’s Unnatural History,” Greece & Rome 37 (1990) 85]. Pliny does seem to have an environmental mission. He criticizes the pollution of rivers and other corruptions of nature [HN 18.3] and emphasizes that the earth pays back what is invested in her [HN 2.155]. Understandably, Wallace-Hadrill notes the temptation to call him “a sort of proto-environmentalist.” Highlighting the economic value of various plants, animals, and minerals is one of the ways Pliny makes his case.

Among economic historians, there has been considerable interest in the encyclopedia’s discussions of coinage and trade. In many respects, however, Pliny’s remarks do not inspire confidence. For example, his description of early Roman coinage includes, as Andrew Burnett once put it, “an astonishing collection of mistakes” [“The Coinages of Rome and Magna Graecia in the Late Fourth and Third Centuries B.C.” Revue suisse de numismatique 56 (1977) 116]; and Michael Crawford calls his account of a late Republican monetary reform “hopelessly confused” [“The Edict of M. Marius Gratidianus,” Proceedings of the Cambridge Philological Society 14 (1968) 3]. Pliny’s tantalizing comments about the drain of money out of the Empire to the east has received much attention. In Book 6, Pliny states that the Empire sent India at least 50 million sesterces per year in exchange for luxury goods such as pepper and, in Book 12 while talking about incense, he says that India, China, and Arabia took at least 100 million sesterces for luxury goods. However, historians have differed considerably on how to interpret these statements or indeed whether to accept them at all.

The eastern outflow numbers are but two of the more than 200 prices and estimates of value which appear in the Natural History. Most of them, unfortunately, are not especially helpful for the economic historian. First of all, many of the prices and values are clearly “conventional figures,” used in much the same way as we speak vaguely of “thousands” or “millions” [Walter Scheidel, “Finances, Figures and Fiction,” Classical Quarterly 46 (1996) 222-38]. Secondly, other numbers in the Natural History are suspect either because the manuscripts disagree or on general principle due to the susceptibility of numbers to be miscopied. Thirdly, many other prices, even if accurate numbers, appear without sufficient contextual information such as in what year and where the goods were sold or even the denomination of the coins used for purchase. Fourthly, Pliny’s long recognized interest in moralizing about luxury means there’s a clear emphasis on excessive prices (both too high and unusually low).

Certainly there are some non-extreme prices. For example, Pliny notes that a modius of regular flour (farina) typically cost 40 asses in his own day [HN 18.90]. But the problematic prices vastly outnumber the useful ones. When Pliny puts the price of an amphora of wine in 121 BCE at 100 sesterces, is this an accurate figure or is he merely using a nice round number to facilitate the calculations he proceeds to make? He says that ten pounds of olive oil cost 1 as in 74 BCE, but this seems to be an artificial price due to the efforts of a particular magistrate, rather than the ‘market price’.

And then there are the prices that, even if they are completely accurate, are not especially helpful. For example, Pliny records that during the Second Punic War a mouse once sold for 200 denarii [HN 8.222]. (Both buyer and seller were besieged and starving.)

Ultimately, while Pliny clearly had an eye for prices, the actual numbers he provides aren’t especially useful. His discussions of price formation, however, do give us considerable insight into the way the market functioned in Pliny’s time as well as into Pliny’s ‘economic thought’. In various places Pliny mentions the role of supply and demand, changes in fashion, lying salesmen and other forms of fraud, as well as labor costs. Late in the work, he pauses to defend his inclusion of so many prices, declaring that he’s well aware of the fact that prices change from place to place and year to year and due to shipping costs and who controls the supply [HN 33.164].

Taken together, Pliny the Elder’s comments suggest a relatively sophisticated understanding of price formation. Historians have been reluctant to attribute much in the way of ‘economic thought’ to the Romans, but Pliny betrays distinct signs of at least “proto-economic thinking.” Although today the best-known Roman economic policy is probably the shortsighted debasement of Imperial silver coinage, the Natural History suggests that at least some elite Romans had a good sense of how the market functioned.

Dr. David B. Hollander is an Associate Professor in the Department of History at Iowa State University